1. Field of the Invention
The present invention relates to an excessive length treatment structure for optical fibers used in electric equipment, for example, in a telecommunication apparatus.
2. Description of the Related Art
With the advent of the full-scale multimedia era in the 21st century, optical fibers are being laid into our homes. This may be called xe2x80x9cFTTHxe2x80x9d (Fiber To The Home).
In order to support such a xe2x80x9cFTTHxe2x80x9d situation, telecommunication lines are required to have a great capacity. When the number of the optical fibers used in telecommunication apparatuses laid in offices is tremendously increased, it brings about a problem that the telecommunication apparatuses become congested with the optical fibers and a treatment for this is troublesome.
FIGS. 1A and 1B show two types, a front access type and a rear access type, of a conventional method for introducing optical fibers into a telecommunication apparatus. In the case of the front access type shown by FIG. 1A, optical fibers 3, which are laid in a vertical direction along sides 2a of shelves 2 of a telecommunication apparatus 1, are dragged into the inside of the shelves 2 from positions adjacent to surfaces 2b thereof. In the case of the rear access type shown by FIG. 1B, on the other hand, the optical fibers 3, which are laid in the vertical direction along rear surfaces of the shelves 2, are dragged into the inside of the shelves 2 from the rear surfaces thereof. Positions of dragging the optical fibers thereinto are not shown.
With regard to the above-mentioned two types, the front access type is mostly used abroad and the rear access type is mostly used in Japan.
Next, a description is given in detail of a telecommunication apparatus using the rear access type with reference to FIG. 2 and FIGS. 3A through 3C.
FIG. 2 is a sectional side view partly showing the inside of the telecommunication apparatus 1. A package 4, which is formed of a substrate module, is accommodated within the shelf 2. A plurality of supporting members 5a are mounted on the shelf 2, extending backwards from the rear surface thereof. A plurality of supporting stands 5b are vertically mounted on respective end portions of the supporting members 5a. The supporting member 5a and the supporting stand 5b are integrally formed.
Thus, space portions A between the rear surface of the shelf 2 and the supporting stands 5b are formed. Within these space portions A, electric cables, which are used for connecting to electric parts arranged in the shelf 2, are laid (not shown). A plurality of the optical fiber 3 are accommodated on the supporting stands 5b, and as shown in FIG. 2 are extended upwards and are dragged into the inside of the shelf 2 from the upper rear surface of the shelf 2.
On the upper shelf 2, there is formed a space 7 which is divided by an inclined plate 8. The optical fibers 3 are extended along the inclined plate 8 so as to be connected to an optical plug 9 which is provided on the upper end portion of the package 4 near the front side of the shelf 2.
In addition, a plurality of apertures (not shown) are formed on a boundary between the space 7 and the package 4. A cooling fan (not shown) is provided in the shelf 2. Heated air, which is generated by the package 4 when the telecommunication apparatus 1 is in use, is discharged, through these apertures and along the inclined plate 8 and further through an aperture (not shown) formed on the upper rear surface of the shelf 2, to the outside.
FIGS. 3A through 3C show the telecommunication apparatus 1 observed from other directions. That is, FIG. 3A is a fragmentary elevation, FIG. 3B is a fragmentary plan view and FIG. 3C is a fragmentary rear elevation.
The telecommunication apparatus comprises excessive length treating portions 6a to 6c which serve to store excessive lengths of the optical fibers 3 by winding the excessive lengths of the optical fibers 3 thereon, so that the excessive lengths are not troublesome. Specifically, as shown in FIG. 3C, the optical fibers 3, in this embodiment, are wound and attached at three excessive length treating portions (excessive length accommodating bodies) 6c which are provided on the rear surface of the shelf 2. Most of the excessive lengths of the optical fibers 3 to be connected to the telecommunication apparatus are thus stored by the excessive length treating portions 6c. 
On the other hand, as shown in FIGS. 3A and 3B, the excessive lengths of the optical fibers 3 are just wound and not fixed at the excessive length treating portions 6a and 6b which are provided on the upper portion of the shelf 2 and on the upper front of the shelf 2, respectively.
In a case where the package 4 is exchanged with another package, the package 4 is drawn out of the front of the shelf 2. At this time, while the package 4 is drawn out, the optical fibers 3 are pulled via a plug 9 connected to a connecting adapter (not shown) fixed to the package 4, and the optical fibers 3 wound on the excessive length treating portions 6a and 6b are thereby pulled and extended so that the package 4 can be smoothly drawn out. After the optical plug 9 connected to the optical fibers 3 is detached from the connecting adapter, the package 4 is removed from the shelf 2.
However, in the above-mentioned conventional telecommunication apparatus 1 of the rear access type, when a plurality of the optical fibers 3 are present, the optical fibers 3 being collected and bound at the excessive length treating portions 6a to 6c become troublesome. This is particularly obvious at the excessive length treating portions provided on the upper front of the shelf 2 and on the upper portion of the shelf 2 as shown in FIGS. 3A and 3B. For this reason, for example, when an optical fiber 3 is added to or removed from the shelf 2, it is difficult to identify which is the optical fiber 3. And when the package 4 is drawn out of the front of the shelf 2, the optical fibers 3 connected to the optical plug 9 may be stretched and the wound optical fibers 3 may exceed their allowable bending strengths and thereby become bent.
It is a general object of the present invention to provide an excessive length treatment structure for optical fibers used in electric equipment including the use of cartridge containers, in which the above disadvantages are eliminated.
Another and more specific object of the present invention is to provide an excessive length treatment structure for optical fibers used in electric equipment, in which a plurality of packages, each of which essentially consist of a substrate module, are accommodated within a shelf, and optical fibers are introduced into said shelf from a rear side thereof opposite to a side from which said packages are drawn out, so as to connect to a corresponding one of said packages via an optical plug at a front side of said shelf, comprising:
a plurality of cartridges which are provided on said rear side of said shelf for accommodating excessive length parts of said optical fibers.
Still another object of the present invention is to provide a cartridge for use in an excessive length treatment structure for optical fibers used in electric equipment, in which a plurality of packages, each of which houses a substrate module, are accommodated within a shelf, optical fibers are introduced into said shelf from a rear side thereof opposite to a side from which said packages are drawn out, so as to connect to a corresponding one of said packages via an optical plug at a front side of said shelf, comprising:
a reel built therein, said reel having a desired diameter on which said optical fiber is wound without exceeding an allowable bending strength, excessive length part of said optical fiber being stored by said reel.
Using the excessive length treatment structure including the use of cartridges, the optical fibers are laid out in an orderly manner, can be identified one by one, and therefore the operation of adding or removing an optical fiber to or from a package can be easily and certainly performed. Hence, when the package is mounted on or removed from a shelf as described above, the optical fibers do not exceed their allowable bending strengths and thereby do not become bent.